BigMac Posted June 26, 2003 Share Posted June 26, 2003 I've had my bird for 5 years now and it's been the best bike I've ever owned. However in that time I've had two occassions of tank slap, one of which I'd like to forget about because of the repair bill it left me with. Both circumstances occured under emergency breaking situations over a road with minor irregularities. Is there anyone that can explain the causes and perhaps possible ways to reduce the occurence or severity? Quote Link to comment Share on other sites More sharing options...
BIG BOY Posted June 26, 2003 Share Posted June 26, 2003 What kind of helmet do you wear???? Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted June 26, 2003 Share Posted June 26, 2003 I have never heard of tank slap from breaking. It happens when the front end is light but I have never had it happen on the bird. Quote Link to comment Share on other sites More sharing options...
SwampNut Posted June 26, 2003 Share Posted June 26, 2003 There's something not right going on. What are the mods to the bike? Suspension changes? What tires? How many miles since the steering head bearings were adjusted? Air pressure? Quote Link to comment Share on other sites More sharing options...
BigMac Posted June 26, 2003 Author Share Posted June 26, 2003 I got the $9.99 special... There's no mods to the bike or the suspension. She's done less than 9500 miles and the steering head bearings have never been adjusted to my knowledge. I'm running Dunlop 208's front and rear (replaced 500 miles ago). Air pressure is and was correct at the time. Each time it was very quick but I feel that I grabbed a little too much brake a little too quickly and momentarily broke the front wheel away from the road. The same thing recently happened to two friends (TL100S and ZXR1200 - btw the Suzuki is very expensive something like $1500/sec). But it annoys me as there's been many times over the years (this bike and others) where I've been able to pull up really hard and fast without any dramas. Curious to know if it was definitely too much brake or that I should look at other possible causes too? I've also watched a 6 week old Bird go down at the 75m mark off the straight prior to a RH turn. The rider explained it as misjudging his braking and also grabbing a little too hard. Quite frankly his tires weren't properly scrubbed in for the track. Quote Link to comment Share on other sites More sharing options...
Warchild Posted June 26, 2003 Share Posted June 26, 2003 What you're describing doesn't sound like a tank-slapper at all. Sounds more like some braking issues.... Quote Link to comment Share on other sites More sharing options...
BigMac Posted June 26, 2003 Author Share Posted June 26, 2003 Definitely tank slap. Characteristic wrist braking movement in the front end. Alas not enough room to ride it out. As for the TL and ZXR I can't be precise as it happened behind me and I wasn't looking in the rear mirror until afterwards. I just have to take the word of my mates (watched the TL slide all the way down the road and run into the back of another rider but thankfully no additional casualties from that event). Quote Link to comment Share on other sites More sharing options...
SwampNut Posted June 26, 2003 Share Posted June 26, 2003 You've completely lost me. You grabbed brake, and the tire skidded? And also the handlebars wobbled back and forth quickly? What is the tire pressure? "Correct" is a very loose number. Got a digital camera? Take a photo from the side of the top of the fork tube as it comes through the triple clamp and where the bars attach. Quote Link to comment Share on other sites More sharing options...
BigMac Posted June 26, 2003 Author Share Posted June 26, 2003 Apologies that I'm not clear. Sorry don't have a camera. Can get one later - what are you looking for? There's was no skid. I've skidded the front tire before but never on the XX. I grabbed front brake on a straight road at 35mph/60kph. Vehicle on right wants to occupy my spot in the time and space continuum. I brake hard but don't swerve. Then on letting go the bars immediately slap violently and then the car decides he wants to slow right down and take left turn. No where to go and not nearly enough control in the bike to shift out to the right. I lean hard and pull her over as best as I can bring her down on the right side and out far enough not to run into the back of the idiot. He doesn't stop. Quote Link to comment Share on other sites More sharing options...
MaXX Posted June 26, 2003 Share Posted June 26, 2003 This is strange. You brake hard (with no problems), then you let off the brake and the clipons start wobbling back and forth in a violent tank slapper (coming from full turn to full turn)??????? Were you back on the gas right away right after braking making the front light???? This bike has been the most solid steed I have ever ridden. It is so heavy and the wheel base so long that it is very difficult to "tank slap" this bike, unless something is very wrong. From what you describe, I am wondering if one of your front calipers is not letting go??? The tires were new and the pressure was correct (between 35 - 40????). No suspension changes. Either I am misunderstanding what happened, or I would narrow it down to something with the brakes (bad caliper, warped rotor?????) or unbalanced tire or bad tire. Sorry I couldn't be of more help. MaXX Quote Link to comment Share on other sites More sharing options...
Grey_XX Posted June 26, 2003 Share Posted June 26, 2003 Not ignoring thread....just completely lost :?: Â :?: Same here. Tank slapper when loading the front beyond what I've ever experienced on any bike. Hugo Quote Link to comment Share on other sites More sharing options...
severdog Posted June 26, 2003 Share Posted June 26, 2003 The only thing that I've had similar to this was when I had a bent front fork tube. When I'd brake hard, the bike would lean left. But it wouldn't slap. A tank slap is a low speed undamped oscillation.....but caused by braking? :???: Quote Link to comment Share on other sites More sharing options...
MaXX Posted June 26, 2003 Share Posted June 26, 2003 The only thing that I've had similar to this was when I had a bent front fork tube. When I'd brake hard, the bike would lean left. But it wouldn't slap. A tank slap is a low speed undamped oscillation.....but caused by braking? :???: Craig, I have seen an 80 MPH tank slapper (on a 929) after coming down off of a wheelie, is that still considered low speed . MaXX Quote Link to comment Share on other sites More sharing options...
AlphaBird Posted June 26, 2003 Share Posted June 26, 2003 I wonder if he is confused with fork chatter---Prior to the fork upgrade---the forks would seriously chatter under max high speed braking Quote Link to comment Share on other sites More sharing options...
Grey_XX Posted June 26, 2003 Share Posted June 26, 2003 I wonder if he is confused with fork chatter---Prior to the fork upgrade---the forks would seriously chatter under max high speed braking That, I would agree with. Hugo Quote Link to comment Share on other sites More sharing options...
RodeRash Posted June 26, 2003 Share Posted June 26, 2003 Possibly the forks bottomed out, and with no suspension left, the tires were bouncing off the pavement, the wheels locked up turned a little sideways, and bang. Quote Link to comment Share on other sites More sharing options...
Grey_XX Posted June 26, 2003 Share Posted June 26, 2003 The only thing that I've had similar to this was when I had a bent front fork tube. When I'd brake hard, the bike would lean left. But it wouldn't slap. A tank slap is a low speed undamped oscillation.....but caused by braking? :???: Craig, I have seen an 80 MPH tank slapper (on a 929) after coming down off of a wheelie, is that still considered low speed . MaXX My contribution to the tankslapper pissing contest :grin: I got a solid_Crap_in_Yer_pants tankslapper at 120-130 mph (WOT in 6, bumpy road, mismatched tires). Hugo Quote Link to comment Share on other sites More sharing options...
SwampNut Posted June 27, 2003 Share Posted June 27, 2003 Alpha's comment on bottoming the suspension is a good one. What do you weigh? I asked for the photos to see the positioning of the fork tubes, to tell if they are not at the standard height. Raising the tubes leads to this sort of problem on many bikes. Overall, let me summarize one thing we're all implying here: Tankslappers just don't happen on this bike. In stock configuration, I would say it is probably impossible to have that happen. Also, tankslappers happen in a light-front situation, not under braking. I've never in my life heard of one while braking. So, not that we don't want to help, but we're stumped. That's why I'd like to start at the basics, like fork tube height. Quote Link to comment Share on other sites More sharing options...
bar10dah Posted June 27, 2003 Share Posted June 27, 2003 I wonder if he is confused with fork chatter---Prior to the fork upgrade---the forks would seriously chatter under max high speed braking Hey! *MY* bike does that! That's called fork chatter? I always wondered if that was normal, but kept forgetting to post about it. Speaking of which, I have a brake rotor question. Don't wanna hog all the posts here, so I'll go make my own. http://www.cbr1100xx.org/forum/viewtopic.p...p?p=23663#23663 Quote Link to comment Share on other sites More sharing options...
BigMac Posted July 8, 2003 Author Share Posted July 8, 2003 Gent's you've all been very helpful. I've got a digital camera and when I work out how to use it this weekend I'll take some happy snaps and post them on my page. I'm interested to know more about what this fork chatter means though? THanks Quote Link to comment Share on other sites More sharing options...
Ripped1 Posted July 8, 2003 Share Posted July 8, 2003 I realize that I am late to this post, but I have experienced my front end "pushing" when I am hard on the binders. I get on the brakes hard, and the front wheel skids, and tries to turn. I can only imagine what would happen if I attempted to brake while leaned over. The suspension also goes pogo on me when this happens. Quote Link to comment Share on other sites More sharing options...
BDAZ XX Posted July 8, 2003 Share Posted July 8, 2003 Mine has done that coasting up to a stop with no brakes applied, let my hands off the bars and she starts to oscillate side to side some AND if I hadn't grabed the bars, I would have been shaken/thrown off. It only does it with worn tires though. New rubber has fixed the problem each time I have experienced it. I had it happen a couple of weeks ago coming into work down a rough section "under construction". I have never heard of any type of TS while UNDER braking though. Quote Link to comment Share on other sites More sharing options...
SwampNut Posted July 9, 2003 Share Posted July 9, 2003 Ripped, give us the story on your bike. Mods? Miles since last fork oil change and oil used? Tires? Pressure? Quote Link to comment Share on other sites More sharing options...
demon Posted July 9, 2003 Share Posted July 9, 2003 My front end only wants to push while riding 2-up real aggressively. My front tire is shot and the pushing should go away with new rubber. The only time I have experianced a bar wobble (not a true tank slapper) while braking on the bird was when I locked the front wheel up in front of the house doing about 25mph when the nieghbor's dog ran out in front of me :evil: . Other than that time, the XX is rock solid (unless you are on the gas and all bets are off :bigshock: with all the tire spinning and light front end). Just my .02 Quote Link to comment Share on other sites More sharing options...
MaXX Posted July 9, 2003 Share Posted July 9, 2003 Randy, I have experienced the exact same thing (with worn tires)!! Not under braking though, just coasting like you said. New rubber fixed it right up. MaXX Quote Link to comment Share on other sites More sharing options...
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